Asda is scrapping its "under 18" pay rate to offer equal rates of pay for all employees doing the same job, regardless of their age.
The supermarket chain has more than 5,000 colleagues who are under 18 working in its stores across England, Scotland and Wales and is investing more than £1.7m in upping their pay rate to match the pay of older workers.
This will see the average worker under the age of 18 take home an extra £300 over the next year.
The move comes in the same week that new age discrimination legislation comes into effect, although the new rules do not force employers to level the playing field for pay in this way.
Until now, it has been common practice for retailers to pay under 18s a lower rate of pay for doing the same job as someone who is over the age of 18.
From this week the national minimum wage for people under 18 is set at £3.30 an hour, while those over the age of 21 will receive £5.35 an hour. This allows employers to pay people under the age of 18 a much lower hourly rate for doing the same job as someone who is a few years older.
Sarah Dickins, head of reward and recognition at Asda, said: "We simply don't see why young people under the age of 18 working in our stores should be paid any less for doing the same job as someone a bit older."
Jude Brimble, GMB national officer for members in Asda, said: "It has been a long-standing GMB principle that people should be paid the rate for the job they do, regardless of age. So this is a very important breakthrough at Asda for young workers."
Asda also has a number of younger workers amongst its 10,000-strong 'seasonal squad' who work for the supermarket for at least 10 weeks every year often over the Christmas period and during the summer months.